Nucleophilic substitution at a saturated carbon atom with retention of configuration: The reaction of trans-2-halo-3-tert-butyloxiranes with phenolates
Whereas reaction of trans-2-chloro or 2-bromo-3-tert-butyloxirane with thiophenolate occurs at C-3 to give 2-phenylmercapto-3,3-dimethylbutanal, phenolates give substitution at C-2 with retention of the oxirane ring and retention of configuration with kinetics that indicate a bimolecular mechanism.